I thought I'd report what I think is a bit of a bug, although I've been able to solve it by deleting the LibFredo6 subfolder from my Users -> Myname -> AppData
A bit of background:
I'm using Sketchup 2019 Pro.
I downloaded your RoundedCorner extension (which is fantastic, by the way) a few days ago into my Downloads folder. I then installed LibFredo6 tools and RoundedCorner from those two files in my Downloads with Window -> Extension Manager, closed and restarted Sketchup, and the extension worked great.
But then....
I decided to clean up my Downloads folder, so moved those two files into a new subfolder I named DownloadedExtensions in my Sketchup folder.
Well, RoundedCorner didn't like that! Something weird was happening: the icon for "rounded corner" actually invoked the sharp corner routine, and the "sharp corner" icon invoked the rounded corner routine (in other words, they were swapped in the menu). That part I could live with, but the routines themselves became all whacked. For example, to create a sphere when everything's working properly I could create a cube of 10x10x10, set an offset of 5, and then run RoundedCorner and voila! Right? Well, for some reason I was getting a cube with rounded edges of about 4 (I think) with holes on two sides and overlaps on the other two.
Anyway, like I said, I fixed the problem by deleting LibFredo6 from AppData (thanks to a suggestion from a previous poster!).
Has anyone ever said to you "you da man!" ???